Originally Posted by dutret
so the top part of the blades are intentionally steeper then the headtube so that you could have a curved blade for with the same offset? Why not just make the headtube steeper?
I guess they were after the spring effect of the fork (I do not think it actually exists, but they obviously thought so back in '70).
Making the headtube steeper would indeed make the clearance the same but the relation between the offset and the trail would be different, affecting the steering.